function ajaxUploadfile(url, otherparams, fileElId, success) {
    var fileEl = document.getElementById(fileElId);
    var form = new FormData();
    for (var p in otherparams) {
        form.append(p, otherparams[p]);
    }
    form.append(fileEl.name, fileEl.files[0]);
    // XMLHttpRequest 对象
    var xhr = new XMLHttpRequest();
    xhr.open("post", url, true);
    xhr.onload = function(data) {
		if (this.status == 200) {
			if (success) {
				success(this.responseText);
			}
		}
	}
    xhr.send(form);
}